Fuel pumping system



Nov. 10, 1942. L. l. ALDRICH FUEL PUMPING SYSTEM Filed March 24, 1941 INVENTOR.

' the pump directly to the intake thereof.

"Patented Nov. 10, 1942 OFFICE FUEL PUMPING SYSTEM Loyd I. Aldrich,Wyoming, Ill.

AlmllcationMarch 24, 1941, Serial-N0. 384,827

8 Claims.

My present invention relates to a fuel system for fuel or other liquidhaving a pump so designed as to eliminate noise.

One object of the invention is to provide a pump which is ofcomparatively simple construction and which has features of 'designwhich give the effect of an air chamber as used in connection with waterpumps or the like to eliminate the noise resulting from unequal flow ofliquid as the impellers of the pump successively pass the outlet of thepump. In this connection, i-t.may be mentioned that impeller type pumps,such as those embodying a pair of meshing gears, have heretofore beenused extensively for the pumping of fuel oil'under pressure to a burnernozzle. Considerable noise hasbeen experienced in the operation of suchpumps where a pressure relief valve acts as a by-pass to return fuel inexcess of that required for operation of the burner nozzle usually fromthe outlet of Such noise is amplified particularly when the supply tankis nearly empty, due to being transmitted into the tank and the endsthereof acting as diaphragms responding to the periodic changes in fuelvelocity as it flows to the pump.

Another object, therefore, of my present invention is to provide a pumpwherein voids-in the fuel are generated by an arrangement whichauxiliary intake being so located with respectto the main intake and theoutlet of the pump that it upplies the fuel required and permitspreferred and desirable embodiment of the invention in the accompanyingdrawing, in which:

Figure 1 is a semi-diagrammatic view showing my pumping system used inconnection with an tip I! for spraying oil into the blast of air tooperation of the pump in such fashion that the voids above referred toare generated.

With these and other objects in view, my invention consists in theconstruction, arrangement and'combination of the various parts of mydevice whereby the objects contemplated are attained, as hereinaftermore fully setforth, point-' ed out in my claims and illustrated in theaccompanying drawing. Although the invention is-sus- I ceptible of avariety of embodiments, it is unnecmunlcates.

produce a combustible mixture, and a by-pass and nozzle opening valvearrangement including a valve stem I3 and a valve plunger l4. The valvestem I3 is normally held seated against a seat 15 by a spring IS. Thespring It may be adjusted by means of a rod H to the desired pressure offuel oil discharged from the nozzle tip l2. v

A supply pipe I8 is connected with the nozzle valve NV for supplying oilthrough a strainer l9 to the valve seat It and to the interior of thepiston l4. Such oil acts against the inner end of the piston II to firstforce it toward theright in Figure 1 against the tension of the springl6, thereby opening the nozzle valve at l3-l5 and finally permittingby-pass of some of the fuel oil through ports l8 into an enlarged spaceIQ of the nozzle valve NV. The oil then flows through a pipe 20 to areturn line 2|. The spring ll will balance the pressure of oil suppliedfrom the pipe II to maintain a given pressure (somewhat lowerthansupplied by the pipe) of discharge from the nozzle tip l2. The excessoil is then returned or by-passed through l8, I9, 20 and 2! to the pump.

The pump itself is indicated generally at P and includes a casing 22having a pair of impellers therein indicated at 23 and 24. The impellersare shown as of the meshing gear type, although they may be'of anysuitable shape. The casing "has a main inlet 25 with which the returnpipe 1| communicates, an outlet with which the pipe ll communicates andan auxiliary inlet 21 with which a fuel supply pipe 28 comnoted, arelocated, as usual, opposite each other standpoints. Accordingly, I haveillustrated .a B5

and substantially in alignment with the meshing teeth of the impellers23 and 24. The auxiliary inlet 21' constitutes my novel contribution tothe art for producing a silently operating pump. The

The pipe 28 extends from a source of fuel supply, such as atank T. v V

The main inlet 25 and the outlet 26,'it will be auxiliary inlet 21 islocated a distance spaced from the main inlet 25, which is greater thanthe distance between the, outer end of two adjacent teeth of theimpeller 24. Accordingly, the auxiliary inlet 21 is at all times sealedby at least one impeller tooth from direct communication with the maininlet 25 and likewise from direct communication with the outlet 26.

My arrangement can be somewhat modified, for instance as shown in Figure2, wherein a second auxiliary inlet 21* is provided for the impeller 23and the fuel supply pipe 28 extends to both this auxiliary inlet and theauxiliary inlet 21. A more mechanically balanced arrangement is thussecured.

Practical operation In the operation of my piunping system, assumingthat the capacity of the pump at the outlet 26 is fifteen gallons perhour g. p. h.) as indicated on the drawing, and that the nozzle tip l2at the pressure set by the spring l6 discharges -a discharge nozzleconnected with the outlet thereof, a pressure relief valve between saidnozzle and said outlet, a return line from said pressure relief valvecommunicating with the main inlet of said pump, and an intake forsupplying additional liquid fuel to said pump, said intake beingconnected with a source of liquid fuel and being located to dischargeinto the space occupied by one of the gears of said pump at a pointspaced a distance from said main inlet which is greater than thedistancebetween the outer ends of two one gallon per hour, then fourteengallons per 23 will accordingly generate voids 29 between any pair ofteeth not in communication with the :main inlet or the outlet 26. In asimilar manner, the impeller 24 will generate a void as at between anypair of teeth not communicating with .the main inlet 25 and theauxiliary inlet 21, but each pocket between adjacent teeth between theauxiliary inlet 21 and the outlet 26 will be filled to capacity (eightgallons per hour). The additional gallon per hour is supplied by thesupply line 28, which gallon is added to the seven received from themain inlet 25.

The voids 29 and 30 are generated by a vaporizing action which takesplace because of the vacuum created and which has the effect ofvaporizing the higher ends of the fuel oil. The voids 29 and 30 thusserve in the capacity of minute air chambers to absorb the shock ofvariations in rate of liquid flow caused by the alternate meshing andunmeshing of the teeth of the im pellers 23 and 24. As soon as thepockets between the gear teeth communicate with the outlet 26, however,the oil is then under pressure to elimi-. nate the voids and preventthem from interfering with the atomizing action at the nozzle tip I 2.

In Figure 2 a better mechanically balanced arrangement is illustrated,although I have found that operation of the arrangement shown in Figure1 is satisfactory and less complicated of manufacture. My arrangementgives the effect of an air chamber in the outlet line from the pumpwhich is satisfactory in connection with pumping water or the like, butin connection with oil is inoperable because the air is absorbed by theoil and finally eliminated, as well as interfering with atomization ofthe oil at the nozzle tip.

Some changes may be made in the construction and arrangement of thepartsof my device without departing from the real spirit and purpose of myinvention, and it is my intention to cover by my claims any modifiedforms of structure or use of mechanical equivalents which may bereasonably included within their scope without sacrificing any of theadvantages thereof.

I claim as my invention:

1. In a fuel pumping system, a gear type pump,

adjacent gear teeth.

2. In a liquid pumping system, a pump casing, a pair of meshingimpellers therein, a liquid discharge element connected with the outletof said casing, a pressure relief valve between said element and saidoutlet, a return line from said pressure relief valve communicating withthe main inlet of said casing, and an auxiliary inlet for supplyingadditional liquid to said pump, said auxiliary inlet being connectedwith a source of liquid supply andbeing located to discharge into thespace in said casing occupied by at least one of said impellers at apoint spaced from said inlet and outlet at greater distance than thedistance between the outer ends of two adjacent impeller blades.

3. In a fuel pumping system, a casing having an inlet and an outlet,gear type impellers therein and meshing with each other, a dischargenozzle connected with said outlet, a return line from said nozzle tosaid inlet, and an auxiliary inlet for supplying additional fuel to saidpump, said auxiliary inlet being connected with a source of fuel andbeing located to discharge into the space occupied by at least one ofsaid gears at a point spaced a distance from said inlet and outletgreater than the distance between the outer ends of two adjacent gearteeth.

4. In a liquid pumping system, a pump, having an inlet and an outletarranged opposite each other, a pair of intermeshing impellers in saidcasing, a discharge pipe connected with said out let, a pressure reliefvalve between said nozzle and said outlet, a retumline from saidpressure relief valve communicating with said. inlet, and an intake forsupplying additional liquid to said pump, said intake being connectedwith a source of liquid and being located to discharge into said casingat a point spaced a distance from said inlet which is greater than thedistance between the outer ends of two adjacent impeller blades.

5. A noiseless pump for supplying fuel oil or the like to a dischargenozzle having a by-pass line comprising a casing, a pair of meshingimpellers therein, said casing having an outlet and a main inletoppositely arranged substantially in alignment with the meshing teeth ofsaid impellers, said outlet being connected to said nozzle, said maininlet being connected with said by-pass line and said casing having anauxiliary inlet connected with a supply of fuel and located tocommunicate with one of said impellers at a point so circumferentiallyspaced from said outlet and from said main inlet as to be at all timesseparated by the impeller blades from direct hydraulic communicationwith said outlet and said main inlet.

6. A noiseless liquid pump to supply liquid to a discharge nozzle havinga relief pressure actuated return line comprising a casing, a pair ofmeshing gears therein, said casing having an outlet and a main inletoppositely arranged substantially in alignment with the meshing teeth ofsaid gears, said outlet being connected with communicate with one ofsaid gears at a point circumierentially spaced from said outlet andsaid'main inlet to be at all times out oi direct hydraulic communicationtherewith, with at least one tooth of a gear interposed between saidauxiliary inlet and said main inlet and at least one tooth of said gearinterposed between said auxiliary inlet and said outlet.

' 7. In a noiseless pump for liquid supplied to a nozzle or the likehaving a return line, a casing, an impeller therein, said casing havingan outlet and a main inlet arranged respectively to supply liquid tosaid nozzle and receive less liquid from said return line and anauxiliary inlet to said casing connected with a supply of liquid andpoint intermediate the outlet and inlet of said 8. In a noiseless pumpfor liquid supplied to a nozzle having a relief pressure actuated returnline, a casing, a pair of meshing gears, said casing having an outletand a main inlet oppositely arranged substantially in alignment with themeshing teeth of said gears, said outlet being connected to said nozzle,said main inlet being connected with said return line, and an auxiliaryinlet to said casing connected with a supply of liquid and located tocommunicate with at least one of said gears at a point circumferentiallyspaced from said outlet and said main inlet.

LOYD I. ALDRICH.

